It does seem to be quite misbehaving. I just tried restarting (after adding 0.23 from all the servers). If this also fails, I have an idea.

Edit Okay, it actually got far enough to start the database import this time, which didn't happen the last time I restarted it. The problem was that the attempts to connect to some of the no-longer-extant servers took so long to time out, that the database connection itself timed out while waiting. I changed the config so it no longer tries to download from those servers.

There is a European folk story called "Stone Soup" or "Axe Soup". In the story, a group of travellers comes to a village and ask for food from the villagers, but are rebuffed. Then they get a clever idea: They start boiling water in a kettle and throw in a big rock. Sure enough, a villager comes around and asks what they are making. "It's stone soup", says one of the travellers. "It's an old recipe, and we're happy to share, but it tastes so much better with onions." The villager runs off to their house to fetch some onions. When they returns, they have a few other villagers in tow. Again, the travellers explain that they are making stone soup, "but it's even better with some carrots". So another villager goes to get carrots. One by one, as new villagers come by, they are told the soup is almost ready, but could use another ingredient. By the end, the kettle is full of tasty and nutritious soup, the cooks fish out the inedible stone, and the entire village, including the travellers, enjoys a delicious meal.

DC:SS was formed when its predecessor Linley's Dungeon Crawl stopped receiving updates, and with the intention of soliciting contributions from the community. Every little feature or bugfix someone adds is a new ingredient for the soup, which is being shared with everyone in the village.

Here is an article, with numbers, on the energy costs of Bitcoin transactions compared to (say) Visa. As of January 2019, a single bitcoin transaction requires about 280,000 times as much energy as a single credit card transaction. This is part of the design of bitcoin, though there has been work on lower-consumption cryptocurrency models (such as Bitcoin Green, Tangle, and others).

When "real" money was backed by gold and other precious metals, it had a much higher energy cost to produce and maintain, but that hasn't been the case for many decades. Now it's mostly a matter of flipping bits in a series of databases; and unlike Bitcoin, only the bits that need to be flipped, rather than a huge amount "wasted" on brute-forcing a cryptographic hash function.

Which isn't to say that the profits and economic activity that drive the need for those transactions don't often derive from exploitation of natural resources, but that's a separate matter from artificially imposing a high energy cost on the transactions themselves.

The algorithm given there finds the largest subset M ⊆ S such that no point in M is dominated by another point in M. However, you (or the SO poster, if that wasn't you) asked for the largest M such that no point in M is dominated by any point in the original set S.

Neil Moore

Assistant Professor (Special Title Series) of Computer Science at University of Kentucky, teaching in the First Year Engineering program and doing research in bioinformatics, especially for fungal endophytes of grasses.